This invention relates to apparatus for forming or folding casings such as sausage casings by shirring the casings on a mandrel or on a tube positioned on a mandrel.
The shirring of casings for meat products such as sausage is an old and well developed technique in the food processing art. Typically a synthetic or natural casing is formed as a long, continuous tube. In order to efficiently and effectively utilize the casing, lengths of it are shirred or folded in pleats transverse to a longitudinal axis of the tube. In this manner, a great deal of casing can be folded and positioned in a sausage or food packing machine, there to be unfolded in a controlled manner according to need as the casing filled with product.
There are numerous prior art patents which disclose equipment for the shirring of casing. Typical among these patents are a series in the name of Kollross including U.S. Pat. No. 4,377,885 entitled "Shaftless Gear Device for Axial Shirring of Synthetic Tubular Material" issued Mar. 29, 1983; U.S. Pat. No. 4,359,806 entitled "Apparatus for Axial Shirring of Plastic Tubular Material Especially Artificial Casing for Sausage Manufacture" issued Nov. 23, 1982; U.S. Pat. No. 4,354,295 entitled "Device for Axial Shirring of Synthetic Tubular Material for Further Processing Especially on Automatic Sausage Stuffers" issued Oct. 19, 1982; U.S. Pat. No. 4,200,960 entitled "Method and Apparatus for Shirring of Synthetic Tubes, Particularly Casings for Sausage Production" issued May 6, 1980; and U.S. Pat. No. 4,370,780 entitled "Process and Device for Axial Shirring of a Tubular Material Using an Air Stream" issued Feb. 21, 1983. The referenced prior art patents disclose rotating wheels positioned to engage against the outside of casing to fold the casing on a mandrel. The particular arrangement of the wheels, the mechanism for driving the wheels and various other supplemental mechanical constructions are disclosed by the prior art patents.
U.S. Pat. No. 4,370,780 discloses an alternative method for shirring casing utilizing an air stream directed obliquely against the casing material in order to effectively pleat or fold the material.
The prior art apparatus for the shirring of casing are useful and effective to provide a high quality shirred casing. However, the apparatus for shirring of casing are extremely expensive and often mechanically complex. Thus, there has remained a need to provide a simple, yet efficient and inexpensive apparatus for the shirring of casing. These are some of the objectives which inspired the development of the present invention.